<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="content-type" content="text/html; charset=UTF-8">
  <title>Read session data</title>

 </head>
 <body><div class="manualnavbar" style="text-align: center;">
 <div class="prev" style="text-align: left; float: left;"><a href="sessionhandler.open.html">SessionHandler::open</a></div>
 <div class="next" style="text-align: right; float: right;"><a href="sessionhandler.write.html">SessionHandler::write</a></div>
 <div class="up"><a href="class.sessionhandler.html">SessionHandler</a></div>
 <div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="sessionhandler.read" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">SessionHandler::read</h1>
  <p class="verinfo">(PHP 5 &gt;= 5.4.0)</p><p class="refpurpose"><span class="refname">SessionHandler::read</span> &mdash; <span class="dc-title">Read session data</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-sessionhandler.read-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="type">string</span> <span class="methodname"><strong>SessionHandler::read</strong></span>
    ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$session_id</code></span>
   )</div>

  <p class="para rdfs-comment">
   Reads the session data from the session storage, and returns the result back to PHP for internal processing.
   This method is called automatically by PHP when a session is started (either automatically or explicity
   with <span class="function"><a href="function.session-start.html" class="function">session_start()</a></span> and is preceeded by an internal call to the
   <span class="function"><a href="sessionhandler.open.html" class="function">SessionHandler::open()</a></span>.
  </p>
  <p class="para">
   This method wraps the internal PHP save handler defined in the
   <a href="session.configuration.html#ini.session.save-handler" class="link">session.save_handler</a> ini setting that was set
   before this handler was set by <span class="function"><a href="function.session-set-save-handler.html" class="function">session_set_save_handler()</a></span>.
  </p>
  <p class="para">
   If this class is extended by inheritiance, calling the parent <em><code class="parameter">read</code></em> method will invoke the
   wrapper for this method and therefor invoke the associated internal callback.  This allows the method to be
   overidden and or intercepted and filtered (for example, decrypting <em><code class="parameter">$data</code></em> value
   returned by the parent <em><code class="parameter">read</code></em> method).
  </p>
  <p class="para">
   For more information on what this method is expected to do, please refer to the documentation at
   <span class="function"><a href="sessionhandlerinterface.read.html" class="function">SessionHandlerInterface::read()</a></span>.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-sessionhandler.read-parameters">
  <h3 class="title">参数</h3>
  <dl>

   
    <dt>
<em><code class="parameter">session_id</code></em></dt>

    <dd>

     <p class="para">
      The session id to read data for.
     </p>
    </dd>

   
  </dl>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-sessionhandler.read-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns an encoded string of the read data. If nothing was read, it must return an empty string. Note this value is returned internally to PHP for processing.
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-sessionhandler.read-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member">
     The <a href="session.configuration.html#ini.session.serialize-handler" class="link">session.serialize_handler</a>
     configuration directive.
    </li>
   </ul>
  </p>
 </div>



</div><hr /><div class="manualnavbar" style="text-align: center;">
 <div class="prev" style="text-align: left; float: left;"><a href="sessionhandler.open.html">SessionHandler::open</a></div>
 <div class="next" style="text-align: right; float: right;"><a href="sessionhandler.write.html">SessionHandler::write</a></div>
 <div class="up"><a href="class.sessionhandler.html">SessionHandler</a></div>
 <div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
